When it comes to songwriting, there's a fine line between inspiration and plagiarism

This week Led Zeppelin were accused of plagiarism. And they're not the first band to take more than just inspiration from those who've gone before

Songwriters are often asked, "Which comes first, the words or the music?", but, in an increasing number of instances, the answer seems to be "Listening to somebody else's record". The easiest way to write a hit song may be to find someone who has written it first.

The latest allegation involves Led Zeppelin's "Dazed and Confused", which is attributed to their guitarist, Jimmy Page, on their 1969 debut album. However, the singer/songwriter Jake Holmes included a song called "Dazed and Confused" a year earlier on his first album, and Page may find it difficult to deny hearing the song as Holmes had opened for Page's previous band, the Yardbirds. It's unclear why Holmes has waited this long to file a complaint. The answer may be simple: you need money for lawyers and you may lose.

Asked by Musician magazine about the similarity between the songs in 1990, Page denied plagiarism and added, "Usually my riffs are pretty damn original." Usually? Well, yes. On that same album, Led Zep recorded "Babe, I'm Gonna Leave You" which was subsequently found to be written by the folk singer Anne Bredon, while "You Shook Me" was originally written by the blues musician Willie Dixon for Muddy Waters.

You could write a book on authenticity (or the lack of it) in Led Zeppelin's recordings. Even "Whole Lotta Love" led to an out-of-court settlement with Willie Dixon's daughter over another of his songs "You Need Love", while "Boogie With Stu" led to a settlement with the publishers of Ritchie Valens' "Ooh! My Head". The irony is that Valens' rock'n'roll song is totally derivative of Little Richard's "Ooh! My Soul".

When I commented to Dr John on some similarity in his repertoire, he told me, "You can't copyright the blues and you can't copyright a title." That is true – and it could be argued that Led Zeppelin were unlucky. Their music is blues-based and many blues songs are similar. Turning to titles, you, me or anyone else can call a song "Strawberry Fields Forever" or "Green Green Grass of Home" and no one can do anything about it. Led Zep were on safe ground when they recorded "Stairway to Heaven", even though it was the title of a 1960 Neil Sedaka hit. If you do nick a title, don't nick the rest of the song as well – as Michael Bolton found to his cost when he reworked The Isley Brothers' "Love Is a Wonderful Thing".

I have never known a songwriter admit to nicking something. Even if he was caught red-handed, he will claim coincidence. He can't do anything else as it may invalidate the rest of his work. In a candid and perhaps unguarded moment, Paul McCartney told Guitar Player in 1990, "What do they say? 'A good artist borrows, a great artist steals' – or something like that. That makes The Beatles great artists because we stole a lot of stuff."

McCartney wasn't admitting to theft. He was saying that The Beatles didn't operate in a vacuum and they assimilated what was happening around them to create original music. Their "yeah, yeah, yeahs" had previously been used by Elvis Presley and The Isley Brothers and their introduction to "I Feel Fine" mimics Bobby Parker's "Watch Your Step".

When McCartney woke up one morning with a beautiful melody in his head, he was sure he had nicked it. After friends told him it was original, he recorded it as "Yesterday". I would speculate that McCartney had heard Nat "King" Cole's "Answer Me, My Love". The mood and the tempo are similar and Nat even sings, "You were mine yesterday, I believed that love was here to stay."

Written in 1963, "All My Loving" was McCartney's first attempt at writing an MOR standard, but play "Kathy's Waltz" from the Dave Brubeck Quartet. You might think that a modern jazz group was improvising around "All My Loving", but "Kathy's Waltz" was recorded in 1959.

In 1969, John Lennon inserted a phrase from Chuck Berry in "Come Together", almost certainly as a tribute, but Berry's publisher was a Rottweiler and demanded recompense. If Lennon had used "Here Come Old Flattop" as his title, he might have been safe. For settlement, Lennon agreed to record some Chuck Berry songs on his album Rock'n'Roll, so it was no great hardship.

George Harrison had a worldwide hit with "My Sweet Lord" in 1971. It is odd that its producer, Phil Spector, never pointed out the similarity with "He's So Fine" by the New York girl group The Chiffons. After Allen Klein fell out with The Beatles, he bought the publishing rights to "He's So Fine" and sued Harrison in revenge. He won and over £1m changed hands. After the case, the judge remarked, "I actually like both songs", to which Harrison replied, "What do you mean 'both'? You've just ruled they're one and the same."

George Harrison had been sued for "unintentional plagiarism", but surely the way his bass line from "Taxman" was copied by the Jam on their No 1 single "Start" was intentional plagiarism. George never sued, perhaps because he regarded it as a compliment and perhaps because he thought he had been unfairly treated over "My Sweet Lord".

With both The Jam and as a solo artist, Paul Weller's borrowings from Sixties records can be regarded as homage. It's more difficult to tell with Oasis as it often seemed that Noel Gallagher was deliberately provoking listeners. There are echoes of The Beatles throughout their work without any one song being direct plagiarism. "Shakermaker" (1994) was sued successfully by the writers of the Coca-Cola ad, "I'd Like to Teach the World to Sing". Gallagher cited "irony" as his defence and after losing, concluded, "We all drink Pepsi."

Oasis were also successfully sued by the satirist Neil Innes for using his melody from "How Sweet to Be an Idiot" on "Whatever" in 1994. This was highly ironic as Innes is famed for his parodies of The Beatles in The Rutles, and has had to share songwriting royalties with them.

What goes around comes around. Oasis could surely have sued the writers of Hear'Say's "Pure and Simple" for borrowing from "All Around the World", but Gallagher laughed at the thought, realising the hypocrisy of doing so.

Far safer, perhaps, to plagiarise the classics as so much is out of copyright – and look at the success of "A Whiter Shade of Pale" (Bach), "I Should Be So Lucky" (Pachelbel) and "You Spin Me Round" (Wagner). Myleene Klass, once in Hear'Say, says, "A lot of rock music plagiarises classical music, but those classical musicians often took things from each other anyway. It used to be a compliment to write variations on a theme."

In 2002 John Cage's publishers claimed that his silent piece from 1952, "4'33", had been plagiarised by Mike Batt on his album Classical Graffiti. Batt maintained that his silence was not the same as Cage's, but nevertheless paid £100,000 to his publishers.

And how unlucky can you be? Al Jolson, George Formby and Elvis Presley are among the stars who added their names to the credits in return for recording the songs. "Avalon" was written by Billy Rose and Buddy DeSylva, but Rose kicked DeSylva out of the way when he learnt Jolson wanted a credit. "Avalon" became a jazz standard, but its melody was based on an aria from Tosca. Puccini's publishers sued and won. Jolson had put his name to a melody that didn't belong to the songwriter in the first place.

In 1983, Men at Work recorded "Down Under", but it wasn't until this week that a court determined that they had plagiarised a folk tune, "Kookaburra Sits in the Old Gum Tree", although their leader, Colin Hay, insisted it was "inadvertent, naive and unconscious".

The Irish folk singer Dominic Behan criticised Bob Dylan for stealing the tune of his "Patriot Game" for "With God on Our Side"; the melodies are identical, but it belongs to a much older song, "The Shores of Lough Erne".

Some plagiarism is so blatant that you wonder if the songwriters ever thought they could get away with it. The Beach Boys reworked Chuck Berry's "Sweet Little Sixteen" as "Surfin' USA", while Marc Bolan's hit for T. Rex "I Love to Boogie" is Webb Pierce's 1956 US country hit "Teenage Boogie" with a few (very few) new words.

The Brazilian musician Morris Albert recorded "Feelings" in 1975 and it became an international hit. Only it wasn't his song. Ten years later, a US court determined that over 80 per cent of "Feelings" had been taken from a French composition, "Pour Toi", and the writers were awarded $500,000.

When Whigfield went to No 1 with "Saturday Night" in 1994, she was sued by both The Equals ("Rub a Dub Dub") and Lindisfarne ("Fog on the Tyne") but both claims were without foundation. She was less fortunate with "Another Day" as it was based on "In the Summertime". I happened to meet Mungo Jerry's front man and songwriter Ray Dorset when "Another Day" was about to be released and I remarked on the similarity. "I know," said Ray, "but I don't want to complain too early as they may withdraw it. Better to wait until it sells and then make a claim." Wise man.

The Rolling Stones now share their credits for "Anybody Seen My Baby?" with k.d. lang, and in 2000, a court determined that The Rolling Stones had "improperly borrowed" two of Robert Johnson's songs, "Love in Vain" and "Stop Breakin' Down". Keith Richards was nonplussed: "There's only one song in the world," he said, "and Adam and Eve wrote it."